Alessandro Island is located in Lake Perris, a reservoir created by the Perris dam built in 1973.

The lake is a popular recreation area and offers many activities including: boating, fishing, hiking, and camping. The dam is chevron shaped with a length of 11,700 ft, height of 130 ft and a capacity of 131,452 acre ft.It is an earth fill dam and is the southern terminus of the California State Water Project.After a seismic hazard was identified in 2005, the water maximum lake elevation was reduced by 20 feet.A seismic remediation project was undertaken in 2014 and is scheduled for completion in 2017.